The objective of this study was to evaluate the effect of the seasons (Summer and Autumn), on live weight, body condition, mass motility, percentage of live spermatozoa, and sperm-cell concentration of Creole roosters (Gallus domesticus) from Mexico. Semen from 35-week-old Creole roosters was collected weekly during 10 weeks in Summer and Autumn, through the dorso-abdominal massage technique. Roosters were individually kept under a constant photoperiod (16 hours light:8 hours dark). The average live weight was 4.5% higher (p<0.05) in Autumn (2.78 kg) than in Summer (2.66 kg), therefore this variable increased with age (r = 0.85, p<0.05). Category 2 of body condition occurred (p<0.05) with higher probability than the others (0, 1 and 3), being practically the same (p>0.05) in Autumn (99.96%) and in Summer (99.81%). On average (and in weeks 1 and 3-10), the percentage of live spermatozoa was higher in Summer than in Autumn. Accordingly, the percentage of live spermatozoa decreased with age (r = -0.82, p<0.05). However, on average, sperm-cell concentration did not change between seasons (p>0.05). In conclusion, Mexican Creole roosters showed higher percentage of live spermatozoa in Summer than in Autumn. Therefore, it is advisable to select these animals of about 2.7 kg and reproduce them in Summer.

The current experiment aimed to evaluate the effects of Pancreatin supplementation at different levels on ileal and fecal digestibility in layertype cockerels. A total of 480-day-old silver brown Hy-Line male chicks were randomly allocated into 5 treatments, 6 replicates (16 birds per pen) arranged in a completely randomized design. Pancreatin enzyme was supplemented on a basal corn-soybean meal-based diet at 0, 250, 500, 750, and 1000 mg/kg and was fed in two growth phases (starter and grower). The results indicated that at the end of the starter stage, except for 1000 mg/kg, dietary Pancreatin supplementation levels increased (p<0.05) the ileal crude protein (CP). Similarly, addition of Pancreatin increased (p< 0.05) apparent ileal amino acids (AA) digestibility (AIAAD) total means of AA (MTAA), means of indispensable AA (MIAA) and dispensable AA (MDAA) with the optimum performance on 250 mg/kg and 500 mg/kg. However, except for histidine and alanine which were negatively affected (p<0.05), and MIAA, MDAA, MTAA which were also positively affected, the addition level at 1000 mg/kg did not affect most of the AIAAD compared to the non-supplemented. Further, Pancreatin supplementation had no effect (p>0.05) on nitrogen digestibility (ND), nitrogen retention (NR), digestible energy (DE), apparent metabolizable energy (AME), dry matter digestibility (DMD), dry matter retention (DMR), and apparent metabolizable energy corrected for nitrogen (AME-n) on fed starter diet. On the other hand, at the end of the grower stage, dietary Pancreatin enzyme supplementation reduced (p<0.05) the ileal CP, MIAA, MDAA, MTAA, AIAAD, AME, AME-n, ND, NR, DE, DMD, and DMR in a dose-dependent manner. The rate of reduction was more marked on Pancreatin addition level 1000 mg/kg. In conclusion, Pancreatin supplementation at 250 mg/kg, 500 mg/kg, and 750 mg/kg improved AIAAD and ileal CP, especially at the young age. The rate of pancreatin enzyme effect was dependent on enzyme supplement level to the ileal CP and individual amino acid.